This invention pertains to a bale forming machine of the type for making round bales. This type of machine picks up crop material such as hay or straw from windrows in a field by means of a pickup head on the machine and forms the picked up material into round bales by utilizing various mechanisms. Some of these machines produce round bales which have a relatively hard core and succeeding layers wrapped upon said core that are relatively uniform but not as dense as the core. This type of bale does not tend to sag when left in the fields but, if such bale is formed from relatively wet material, the core tends to rot after a period of time. In North America, because there is relatively little baled material which is of a very wet nature, baling machines which form round bales with hard cores have been popular. In certain sections of Europe, as well as other areas in the world, where the climate is much more moist than in North America, it has been found that if a round bale is formed with a soft core, it is possible to prevent rotting of the core. Bales formed with soft cores generally have more dense or harder outer layers or shells but such round bales tend to sag when left for any substantial amount of time in the field.
Typical examples of round baler machines developed heretofore for purposes of forming round bales with soft cores comprise the subject matter of prior U.S. Pat. No. 4,119,026, dated Oct. 10, 1978, in the name of Sacht, and No. 4,212,149, dated Jul. 15, 1980, in the name of Krone et al. In the Sacht patent, a series of endless conveyor belts extend around sets of rollers or drums, the drums being mounted on transverse axes extending between opposite sides of the baler frame, the conveyor belts being arranged in a generally circular pattern with a space provided between two adjacent sets of conveyor belts to comprise an opening into which material is delivered by a pickup head. The conveyor belts move the material generally into a loose spiral and ultimately form a soft core around which somewhat more dense layers are wound until a bale of desired diameter is formed. Furnishing and maintaining the plurality of conveyor belts necessary in this machine results in considerable expense.
In the patent to Krone, a hollow cylindrical winding compartment is provided with a bottom gap through which the crop material is fed by a pick-up device into a substantially cylindrical boundary wall, the inner surface of the boundary wall is swept by an endless apron in the form of transverse slats spaced from each other with the ends thereof connected to endless chains which move in annular channels or guides to ensure that the inner portion of the apron will remain adjacent the inside of the cylindrical boundary wall, while the outer portion of the apron rides around the exterior of the cylindrical boundary wall. In general, the apron comprises a substantially C-shaped configuration, the ends of which are spaced to form the bottom gap referred to above and the apron also extends around a pair of spaced drive rollers or sprockets located adjacent the opposed ends of the C-shaped configuration.
Additional prior U.S. Pat. No. 4,434,607, dated Mar. 6, 1984, in the name of Campbell, is an example of a baling machine adapted to form round bales with hard cores. To prevent the machine from being overfilled, a trip lever and an actuating lever serve to interrupt the driving of the pickup header of the machine and thereby prevent structural damage to the machine.
The present invention is directed to a machine of the type to form round bales with relatively soft cores surrounded by layers of crop material becoming more dense toward the outer surface of the bale. The mechanism by which such bales are formed is simpler and less complex than similar mechanisms of other machines as described above.